package com.youxin.foundation.security;

import java.security.DigestException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * 
 * @author yingde.cao
 *
 */
public class Sha1Utils {
	/*
	 * SHA1加载
	 */
	public static String sha1(String decript) {
        try {
            MessageDigest digest = MessageDigest
                    .getInstance("SHA-1");
            digest.update(decript.getBytes());
            byte messageDigest[] = digest.digest();
            // Create Hex String
            StringBuffer hexString = new StringBuffer();
            // 字节数组转换为 十六进制 数
            for (int i = 0; i < messageDigest.length; i++) {
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
                if (shaHex.length() < 2) {
                    hexString.append(0);
                }
                hexString.append(shaHex);
            }
            return hexString.toString();
 
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }
	/** 
     * SHA1 安全加密算法 
     * @param maps 参数key-value map集合 
     * @return 
     * @throws DigestException  
     */  
    public static String sha1(Map<String,String> maps) throws DigestException {  
        //获取信息摘要 - 参数字典排序后字符串  
        String decrypt = getOrderByLexicographic(maps);  
        try {  
            //指定sha1算法  
            MessageDigest digest = MessageDigest.getInstance("SHA-1");  
            digest.update(decrypt.getBytes());  
            //获取字节数组  
            byte messageDigest[] = digest.digest();  
            // Create Hex String  
            StringBuffer hexString = new StringBuffer();  
            // 字节数组转换为 十六进制 数  
            for (int i = 0; i < messageDigest.length; i++) {  
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);  
                if (shaHex.length() < 2) {  
                    hexString.append(0);  
                }  
                hexString.append(shaHex);  
            }  
            return hexString.toString().toUpperCase();  
  
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
            throw new DigestException("签名错误！");  
        }  
    }  
    /** 
     * 获取参数的字典排序 
     * @param maps 参数key-value map集合 
     * @return String 排序后的字符串 
     */  
    private static String getOrderByLexicographic(Map<String,String> maps){  
    	List<String> keys=new ArrayList<>(maps.keySet());
        return splitParams(lexicographicOrder(keys),maps);  
    }  
//    /** 
//     * 获取参数名称 key 
//     * @param maps 参数key-value map集合 
//     * @return 
//     */  
//    private static List<String> getParamsName(Map<String,Object> maps){  
//        List<String> paramNames = new ArrayList<String>();  
//        for(Map.Entry<String,Object> entry : maps.entrySet()){  
//            paramNames.add(entry.getKey());  
//        }  
//        return paramNames;  
//    }  
    /** 
     * 参数名称按字典排序 
     * @param paramNames 参数名称List集合 
     * @return 排序后的参数名称List集合 
     */  
    private static List<String> lexicographicOrder(List<String> paramNames){  
        Collections.sort(paramNames);  
        return paramNames;  
    }  
    /** 
     * 拼接排序好的参数名称和参数值 
     * @param paramNames 排序后的参数名称集合 
     * @param maps 参数key-value map集合 
     * @return String 拼接后的字符串 
     */  
    private static String splitParams(List<String> paramNames,Map<String,String> maps){  
        StringBuilder paramStr = new StringBuilder();  
        for(String paramName : paramNames){  
            paramStr.append(paramName);  
            for(Map.Entry<String,String> entry : maps.entrySet()){  
                if(paramName.equals(entry.getKey())){  
                    paramStr.append(entry.getValue());  
                }  
            }  
        }  
        return paramStr.toString();  
    }  
}
